Underground Utilities in Tucson, AZ

Underground electrical distribution and related utility work — primary and secondary feeders, transformer and switchgear foundations, and utility tie-ins.

This work is performed under our Arizona ROC KA Dual Engineering license (#312437). See the full A– General Engineering scope it carries, including A-17 Electrical and Transmission Lines for right-of-way and utility-side work.

What We Provide

Underground Utilities — in detail

Primary and secondary feeders, transformer pads, and utility tie-ins — here is how we put electrical distribution in the ground and coordinate it with TEP and Trico.

Primary & Secondary Distribution

  • Primary underground distribution — We install the medium-voltage primary that feeds pad-mounted transformers and switchgear across a site or campus, coordinated with the serving utility.
  • Secondary feeders and services — From the transformer to the building we install the secondary feeders and services that bring usable power to the gear.
  • Transformer and switchgear foundations — We set the pads, grounding grids, and stub-ups that pad-mounted transformers and switchgear sit on.

Utility Tie-Ins & Crossings

  • Utility tie-ins — We coordinate and make the connections to the serving utility's system, on their schedule and to their standards.
  • Wet-utility coordination — We coordinate water, sewer, and storm crossings with the electrical and communication pathways so separations and clearances meet code.
  • Grounding grids and systems — We install the grounding grids and systems that keep underground equipment safe and code-compliant.

Self-Performed

  • One crew, trench to terminations — Because we self-perform the trenching, the duct bank, and the electrical, the underground utility scope stays with one accountable team.
  • Sequenced with the building — We sequence the underground with the building schedule so power is where it needs to be, when it needs to be there.

Utility Coordination

Who trenches, who pulls — how a TEP job actually splits

Underground work on a TEP or Trico system runs on a clean division of labor. Knowing exactly where the contractor's scope ends and the utility's begins — and building to the utility's standards from day one — is what keeps a project out of the back of the utility's scheduling queue.

What the contractor builds

On a typical TEP project, we perform all of the civil work: excavating the trench, installing the conduit and duct bank to TEP's construction standards — the specified size, sweep radius, spacing, and concrete encasement where the standard calls for it — forming and pouring the transformer or switchgear pad, installing the grounding, and backfilling with the specified bedding and compaction. Before we call for the utility, we proof every raceway with a mandrel and leave a pull rope in place, because TEP will not schedule a cable pull into a duct that has not been proven clean.

What TEP installs

TEP furnishes and pulls its own primary cable, makes the medium-voltage terminations, sets the pad-mounted transformer or switchgear, and energizes the system. No contractor pulls primary on the utility's side of the service point. That means the trench, conduit, and pad have to pass the utility's inspection before a TEP crew ever mobilizes — and a failed inspection sends the project back into their queue.

Inspection hold points we plan around

The sequence is predictable, and we build the schedule around it: Arizona 811 Blue Stake locates before any excavation; an open-trench inspection of conduit, sweeps, and separations before a yard of backfill goes in; a pad and grounding check before the utility will set equipment; and compaction verification where the route crosses pavement or public right-of-way. Larger disturbances also trigger Pima County PDEQ dust-control permitting, which we carry as part of our site civil infrastructure scope.

The paperwork side of a new service — the application, load data, easements, and scheduling — is its own subject. Our TEP new service requirements guide walks through that process step by step, and our TEP standards hub indexes the construction standards this page keeps referring to.

Scope Ownership

Primary vs. secondary — and how the trench gets shared

Two questions decide most of the cost and coordination on an underground job: who owns each piece of the system once it is energized, and what shares the excavation on the way there.

Primary side

The medium-voltage primary — from the utility's existing system to the transformer — is utility-owned once energized, even though the contractor built the trench, conduit, and pad it occupies. It is designed to TEP's standards and the National Electrical Safety Code, inspected by TEP, and maintained by TEP for the life of the installation. Our job is to hand the utility a raceway system its cable can live in for fifty years.

Secondary side

From the transformer's secondary terminals to the service equipment, the installation is customer-owned and NEC-governed — burial depths per NEC Table 300.5, conductor sizing, and the grounding electrode system are our responsibility as the electrical contractor, and the owner's to maintain afterward. Because we hold both the engineering and electrical licenses, the secondary design and installation stay under one roof.

Joint trench

Power and communications routinely share one excavation on commercial sites — a joint trench is cheaper than parallel trenches and keeps the site from being cut twice. Inside it, each occupant keeps its required separation: communications typically ride above or beside the power with defined horizontal and vertical clearance, while gas and wet utilities generally stay in their own trenches at their own code-required distances from power. We lay out the trench section so every utility's standard is satisfied before anything is buried.

Boring vs. open cut

Across unimproved ground, open-cut trenching is almost always the economical answer. Directional boring earns its premium where the route crosses live streets, finished pavement, mature landscaping, or utilities that cannot be disturbed — and in public right-of-way it is often the only method the permit allows. We pothole existing utilities to verify depth before a bore is committed, because a bore head finds a water main the hard way only once.

Transformer pads, clearances, and desert ground

A pad-mounted transformer needs more than a level slab. The utility's standard drawings govern the pad dimensions, conduit window, and grounding, and they require clear working space around the equipment — commonly on the order of ten feet in front of the doors and several feet at the sides and rear, confirmed against the current TEP standard drawing — kept free of walls, landscaping, and parking. We verify the pad location against the standard and the site plan early, because moving a transformer after the duct bank is in the ground is the most expensive relocation on the site.

Tucson ground conditions shape the means and methods. Caliche — the cemented layer that sits under much of this valley — can turn a routine trench into hammer work, which is why we bid off potholes and soil data rather than optimism. A July monsoon cell can put standing water in an open trench overnight, so during storm season we open only what we can inspect and backfill in the same cycle. And 110°-plus summer days mean pads and encasement pours go in early with hot-weather concrete practice. It is also why we run our own Cat fleet — production in this ground is a function of the iron on site.

Where It Applies

Markets we serve

From Tucson, our underground utility work serves commercial developments, industrial facilities, and municipal projects on TEP and Trico systems.

  • Site and campus power
  • Commercial developments
  • Industrial facilities
  • Municipal and public
  • Mixed-use

The Design-Build Advantage

Designed, self-performed, and accountable

We dig, install, and terminate — one contract from the trench to the gear. That keeps utility coordination, inspections, and backfill on a single schedule, with no sub waiting on a sub.

Back to Underground
  • Primary and secondary self-performed end to end
  • Utility coordination handled in-house
  • Trenching, duct bank, and wire by one team
  • Sequenced with the overall project schedule

FAQ

Underground utility questions, answered

Planning underground distribution on a TEP or Trico system? Start with our TEP new service requirements guide, or check a raceway with the free conduit fill calculator.

Who digs the trench and who pulls the cable on a TEP job?

The split is consistent: the contractor builds everything passive — the trench, conduit, concrete encasement, transformer pad, grounding, and backfill, all to TEP construction standards — and TEP furnishes and pulls the primary cable, makes the terminations, and sets and energizes the transformer. We self-perform the entire contractor side, from excavation to the proven, mandrel-tested raceway.

How long does TEP coordination take on a new underground service?

It depends — on the service size, whether new primary or an easement is involved, and how deep the utility's design and construction queues are — so the honest answer is to start early. We engage TEP during design rather than after permits, so the utility's requirements are in the drawings before the trench is priced. Our TEP new service requirements guide walks through the application and scheduling process.

What conduit does TEP require for underground primary?

TEP's construction standards dictate the conduit material, size, burial depth, sweep radius, and where concrete encasement is required, and the details vary with voltage and location. We build to the current standard drawings and confirm project-specific requirements with the TEP inspector before the trench opens — our TEP standards hub indexes the documents that govern this work.

Can power and communications share the same trench?

Usually, yes. A joint trench with electric and communications is common on commercial sites and cheaper than cutting parallel trenches, provided each occupant keeps its required horizontal and vertical separation. Gas and wet utilities generally run in their own trenches at their own required distances from power. We design the trench section around every utility's standard before anything is buried.

When do you bore instead of open-cutting?

Open cut wins on cost across unimproved ground. Directional boring earns its premium under live streets, finished pavement, mature landscaping, and existing utilities that cannot be disturbed — and in public right-of-way it is often the only method the permit allows. In Tucson, caliche and cobble can slow a bore, so we pothole the crossings and verify conditions before committing to either method.

Who owns the underground system once it is energized?

On most commercial services the utility owns and maintains the primary cable and the transformer, even though the contractor built the trench, conduit, and pad they occupy. Everything from the transformer's secondary terminals to the building — conductors, raceway, and service equipment — belongs to the customer, which is why the secondary deserves the same duct-bank quality as the utility side. Request a bid and we will scope both sides in one package.

More Underground

Related capabilities

Explore the rest of our underground scope, or see the full underground overview.

Have a project that needs underground utility work?

Tell us the service size and the route. We'll handle the Arizona 811 Blue Stake and utility coordination and come back with a plan.

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